1. Field of the Invention
The present invention relates generally to air pollution control equipment, and more particularly to a wet electrostatic precipitator (wet ESP) which makes use of wetted nanoparticles-coated dispersion plates to keep the collection surfaces clean and pulse jet for keeping the discharge wires clean.
2. Description of the Related Art
General Electrostatic precipitators (ESPs), having dry and wet types, have been widely used to remove particles emitted from various industrial processes. When particles are introduced into the ESPs, they are charged by diffusion and field charging mechanism and are collected on the collection electrodes by electrostatic force.
The wet ESPs have been developed to control a wider variety of particulate pollutants and exhaust gas conditions compared to the dry ESPs, especially for the dust which is sticky, corrosive or has high resistivity. The periodic or continuous scrubbing water flow used to wash the collection electrode surfaces was found to increase the collection efficiency and prevent particle re-entrainment due to rapping, which occurs in dry ESPs.
The U.S. Pat. No. 5,395,430 disclosed a wire-in-tube wet ESP in which the scrubbing water was introduced onto a diamond-shaped plate, which was used to equalize the water flow, and then flowed into the inner surface of the collection electrode to remove the collected particles. However, high flow rate of scrubbing water was used to generate uniform water film on the internal wall of the collection tubes which resulted in a thick water film, thus decreasing the electric field strength due to water resistivity. Besides, deposition of particles onto the discharge wires forms dust cakes, which decrease the corona intensity and the lifetime of the discharge wires.